This invention relates generally to hypodermic needles and catheters which are adapted to inject substances into humans, animals, and/or to withdraw specimens therefrom. More particularly, the present invention relates generally to protective devices which are employed for shielding the needle of a hypodermic syringe, catheter or other injecting or withdrawing device after usage thereof.
The vast majority of hypodermic needles are disposable type needles which are discarded after usage. The shielding of the sharp end of the hypodermic needle is of critical concern to health practitioners both in relation to needle disposal and to handling the needle. Accidental exposure to the sharp end of the needle can have very serious and even fatal health consequences. For example, the needle may be contaminated with diseases such as hepatitis and AIDS. It is well documented that accidental puncture with a contaminated needle could result in infection with such diseases. Because the hypodermic needle is frequently used during times of emergency or high stress, it is highly desirable that the needle be immediately shielded after usage in a reliable and efficient manner which provides a high degree of protection from accidental puncture.
A wide variety of different types of devices for shielding a hypodermic needle against inadvertent needle exposure have been advanced. Protective cap-like members for enclosing the sharp end of the needle are incorporated into a number of shield devices. Mitchell U.S. Pat. No. 4,631,057 discloses a shielded needle wherein a needle guard is mounted on the body of a hypodermic syringe. The needle guard moves from the retracted position at which the needle is exposed for usage to an extended position at which the guard shields the needle. The needle guard can be locked in the extended position by inter-locking members carried by the needle guard and a collar which is mounted on the body of the syringe.
Sampson et al U.S. Pat. No. 4,573,976 discloses a shielded needle wherein a needle guard is mounted on the body of the syringe. In an extended position, the needle guard obstructs access to the point of the needle. In a retracted guard position, the point of the needle is exposed for usage. The guard may be releasably retained in a retracted position. Interlocking members on the syringe body are responsive to generally axial movement of the guard to the extended position to prevent reverse movement of the guard toward the retracted position.
In U.S. patent application Ser. No. 093,750, filed on Sept. 8, 1987, entitled "Protective Sheath for Hypodermic Needle", a new and improved protective needle sheath for a hypodermic needle comprises a protective shield assembly which is suitably mounted to the base of the hypodermic needle for shielding the needle point in an extended axial position. The protective shield assembly is axially spaced from the needle point in the retracted position to permit exposure of the needle. In one embodiment, the shield assembly comprises a pair of telescopic concentric, generally cylindrical shields. A mounting flange projects transversely from the needle base. The inner shield has a generally cylindrical surface which axially slides across the peripheral edge of the mounting flange. The sleeve has an end-wall portion and an interior locking means engagable with the flange to lock the inner shield in a fixed axial position wherein the shield encloses a portion of the needle. A radially projecting lock ring is positioned at the opposite distal end of the inner shield. The outer shield has a generally cylindrical surface which axially slides across the peripheral edge of the ring. At a proximal end of the second shield, an interior locking means is engagable with the lock ring to lock the outer shield in fixed axial position with the inner shield whereby the outer shield encloses the needle point and a portion of the needle. In one disclosed embodiment, a flap extends interiorily to the protective guide sleeve. The flap slides along the needle and obstructs axial access to the sharpened needle point in the extended position of the protective shield.
In U.S. application No. 140,566, filed on Jan. 4, 1988, and entitled "Corrugated Protective Sheath for Hypodermic Needle", a protective sheath is mounted to the base of the needle. The protective sheath has a flexible corrugated form which is expandable from a retracted, folded configuration to an extended expanded configuration for shielding the needle point. One end of the protective sheath is anchored in a fixed relationship with the base of the needle. A flap-like member extends interiorily at the opposing leading portion of the shield. In the extended position, the flap cooperates with the sheath to obstruct access to the sharpened needle point to thereby prevent inadvertent puncture.